correlational
Taking glycine before bed might help people get into deep sleep faster, according to sleep monitoring equipment.
Scientific Claim
Glycine ingestion (3 g) before bedtime was associated with reduced sleep latency to slow wave sleep in individuals with chronic unsatisfactory sleep, as measured by polysomnography.
Original Statement
“Glycine improved subjective sleep quality and sleep efficacy (sleep time/in-bed time), and shortened PSG latency both to sleep onset and to slow wave sleep without changes in the sleep architecture.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study is an observational cohort with unclear randomization and control group status, so causal language ('shortened') is inappropriate. Only association can be claimed.
Evidence from Studies
No evidence studies found yet.